3.4. Why is America called bei?

Sign: 在日米軍基地 "US Military Base in Japan"

The kanji 米 (Bei) used to mean "The United States of America" in
words like beikoku "America" or beigun "American military"
is actually the kanji for `rice'. Why is it used to mean "America"?
This originates from writing Amerika (America) in kanji as
亜米利加, in the Chinese style. Here the 米 kanji is the second
kanji in the word. This style of writing dates from an era in which
kanji was used more frequently than now.